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## Homework Statement

Unpolarized light is incident on a system of three polarizers. The second polarizer is oriented at an angle of 33.0° with respect to the first and the third is oriented at an angle of 45.0° with respect to the first. If the light that emerges from the system has an intensity of 2.3 W/m2, what is the intensity of the incident light?

## Homework Equations

I

_{out}=I

_{in}cos

^{2}[tex]\theta[/tex]

## The Attempt at a Solution

I know that after I

_{0}passes through the first polarizer, it is 1/2I

_{0}. After it passes through the second, I thought it would be 1/2I

_{0}cos

^{2}(33), and after it passes through the third, 1/2I

_{0}cos

^{2}(33)cos

^{2}(45).

This would all equal 2.3, which I was given.

So I set up my final equation as:

1/2I

_{0}cos

^{2}(33)cos

^{2}(45) = 2.3, or

I

_{0}= 2.3 / (1/2cos

^{2}(33)cos

^{2}(45).

I solved and got 13.08, but that is incorrect. Can anyone offer any insight? Thanks.